Generally, a conventional image reading apparatus is capable of reading images and transmitting image data representing the read image to an image processing apparatus connected to the same LAN. Specifically, the image reading apparatus performs a so called push scan. In the push scan, a user issues a command to the image reading apparatus to initiate scanning. Subsequently, the image reading apparatus reads an original to generate image data and transmits the image data to the specified information processing apparatus on the LAN.
When the user of the conventional image reading apparatus performs an operation on the apparatus, i.e., pushes a button, for instructing the image reading apparatus to start scanning, the image reading apparatus transmits information specifying a scan start (scan key event) to the information processing apparatus. Through a driver installed on the information processing apparatus, the information processing apparatus transmits a scan start request to the image reading apparatus. After receiving the scan start request, the image reading apparatus reads the image and transmits the resulting image data to the information processing apparatus.